1. Field of the Invention
The present invention relates to an image forming apparatus such as a copier and a printer, and a sheet conveyance apparatus, and more particularly to an image forming apparatus for improving jam-handling capability and a sheet conveyance apparatus included therein.
2. Discussion of the Background
Background image forming apparatuses such as copiers, printers, and facsimile machines are provided with an accessible sheet conveyance path arranged in the vicinity of a registration roller so that a jam clearance operation is easily performed. For example, one background image forming apparatus has a configuration in which covers of an automatic duplex apparatus and a secondary transfer unit are opened so that a sheet conveyance path around a pair of registration rollers may be accessed.
When a jammed sheet lies between a position of the pair of registration rollers and a position of an image forming unit, pulling out the jammed sheet toward an upstream side of the pair of registration rollers in a sheet conveyance direction causes an image formed on the jammed sheet with toner, ink, or the like to adhere to the pair of registration rollers, resulting in a stain on the pair of registration rollers. Therefore, the pair of registration rollers is provided with a one-way clutch in a bearing thereof to regulate reverse rotation of the pair of registration rollers so that the jammed sheet cannot be pulled out toward the upstream side of the pair of registration rollers in the sheet conveyance direction.